Resonant scattering of light by excitonic rough surfaces

The Rayleigh-Fano approach is used to study the scattering of p-polarized light from the deterministically shaped rough surface of a semiconductor in the vicinity of an isolated excitonic transition. Nonlocal effects are accounted by the Hopfield and Thomas dielectric function. A perturbative formalism is developed to calculate the amplitudes of the scattered fields up to second order on the roughness height. Numerical results are presented for the ${\mathit{A}}_{\mathit{n}=1\mathrm{}}$ excitonic transition of CdS using different choices of additional boundary conditions. Comparisons are made with the local model calculations and discussed in terms of resonant elastic scattering. The differential reflectance spectra peaks are also shown and interpreted as surface-exciton-polariton coupling.